LRV and URV stand for Lower Range Value and Upper Range Value, respectively. In the context of level measurement using a differential pressure transmitter, LRV and URV represent the minimum and maximum levels that the transmitter is calibrated to measure within a specific range.

Here's how to obtain LRV and URV for level measurement using a differential pressure transmitter:

1. Determine the Measurement Range:

   • Determine the desired measurement range for the level application. This range represents the minimum and maximum levels that need to be measured in the tank or vessel.

2. Select the Differential Pressure Transmitter:

   • Choose a suitable differential pressure transmitter that meets the requirements of the application, including the desired measurement range, accuracy, pressure ratings, and environmental conditions.

3. Calculate the Differential Pressure Range:

   • For level measurement using a differential pressure transmitter, the differential pressure (DP) is proportional to the level height in the tank. Calculate the differential pressure range required to cover the desired measurement range.
   • Differential Pressure Range = URV - LRV

4. Assign LRV and URV Values:

   • Assign appropriate values for LRV and URV based on the calculated differential pressure range and the specific requirements of the application.
   • LRV: This corresponds to the minimum level in the tank, where the differential pressure is at its lowest value. It is typically set to the reference (zero) level or the lowest expected level in the tank.
   • URV: This corresponds to the maximum level in the tank, where the differential pressure is at its highest value. It is typically set to the highest expected level in the tank.

5. Calibration and Configuration:

   • Calibrate the differential pressure transmitter using the assigned LRV and URV values. This involves adjusting the transmitter's zero and span settings to ensure accurate measurement within the specified range.
   • Configure the transmitter to output a linear 4-20 mA signal corresponding to the measured differential pressure range between LRV and URV.

6. Installation and Testing:

   • Install the differential pressure transmitter in the appropriate location on the tank or vessel, ensuring proper mounting and connection to the process.
   • Perform testing and verification to ensure that the transmitter accurately measures the level within the specified range, and that the output signal corresponds correctly to the level variations in the tank.

By following these steps, you can obtain LRV and URV values for level measurement using a differential pressure transmitter and ensure accurate and reliable measurement within the desired range.